Generally, a solid-state imaging apparatus such as an image pickup apparatus or an image sensor is constituted by a light receiving section for picking up an optical image signal and a shifting section for shifting a picked-up image signal. If various defects incident to the manufacturing process of the solid-state imaging apparatus take place in the light receiving section or the shifting section, black or white lines in the form of a black and white stripe pattern is displayed on the screen, thereby degrading the quality a picture reproduced thereon. When the light receiving section is constituted by PN photodiodes, for example, the defective picture is thought due to a large leakage in the PN photodiode which results from defects in a diffused layer caused in the manufacturing process. The large leakage causes excessive carriers to flow into shifting stages via transfer MOS transistors connected thereto and in addition, the excessive carriers prevailing in one stage of the shifting section immigrate into adjacent stages, resulting in a so-called overflow. If the overflow carriers prevail in the shifting section in one column, the one column is displayed as a white line on the screen.
When the shifting section is constituted by charge transfer devices such as a BBD or CCD device, irregularities in the thickness of an insulating oxide film or formation of pinholes in the insulating oxide film may be produced in the manufacturing process. The pinholes thus formed in the insulating film cause the transfer pulse voltage to be sent to the shifting stage as a spurious information signal. The spurious information signal is added to optical information and displayed as a defective black or white line on the screen.
Various approaches have been tried to improve the manufacturing process in order to eliminate the defective stripe pattern on the screen incident to the manufacting a process, however difficulties in obtaining a high yield rate of production of the solid-state imaging apparatus have been encountered as such an apparatus occupies a much larger area, e.g., several to ten square mm, than other IC circuits. Accordingly, for correcting the stripe pattern it has also been proposed to employ an external circuit which detects the position of a line defect and corrects the same. This method uses an ROM (Read Only Memory) for storing the position and size of a line defect. More particularly, the size of the line defect is quantized into a digital value and stored in the ROM. Then, a portion of an image signal corresponding to the position of the line defect and the information from the ROM are differentiated to correct the line defect. This method is, however, disadvantageous as it requires the provision of separate ROMs for separate devices and a complicated external circuit.
Essentially, a solid-state imaging apparatus is a finely fabricated, large-area integrated circuit device and if subjected to defects in the light receiving section caused in the manufacturing process, it suffers from line defects such as white lines or black lines displayed on the screen.
Line defects are displayed as black or white lines on the screen even when the light receiving section of the solid-state imaging apparatus is not irradiated with light. If the solid-state imaging apparatus is provided with a light receiving section for picking up an optical signal representative of an optical object which is usually converted into an electric signal and a light shielded section shielded from the incident light, it is possible to obtain a signal representative of the line defect through the light shielded section and a signal representative of a mixture of optical signal and line defect through the light receiving section.